King Neptune's Adventure is an unlicensed adventure game created for the Nintendo Entertainment System by Color Dreams. Players play as King Neptune, as they venture though ships, oceans and Atlantis.

Eight of King Neptune's treasures have been stolen over the years, including his most powerful one, the magical Orb of Peace. Those under the sea are worried, as peace is at risk. Players as King Neptune must return the Orb of Peace to King Neptune's castle and restore peace to his oceanic kingdom. King Neptune is armed with bouncing lightshots, as well as bubble bombs. Players collect health and bombs by destroying enemies. The 8 treasures can be recovered by beating bosses or with the help of the dolphins.